1. Field of the Invention
The present invention relates to a linear motor supporting apparatus for a linear motor elevator, and more particularly to an apparatus for dampening a load from a stator of a linear motor, which varies according to the relative displacement between the stator and guide rail.
2. Description of the Conventional Art
Conventionally, a cable type elevator requires a more spacious machinery room for developing the driving force. However, in order to overcome such problems, the elevator adopting the linear motor attracts wide attentions due to its vibration- and noise-abatement features and even smaller space requirements for installation of the driving machinery.
Referring to FIGS. 1 and 2, there is shown an elevator equipped with a linear motor. In the figure, the passenger car is connected with cable 6 for controlling the ascent and descent thereof.
The other ends of the cable 6 are connected to a square frame member 4 in which is disposed a rotor 2, having a bore hole for slidably receiving a stator 1 and linearly going up and down along the stator 1, for driving the car 5 is disposed. Here, one end of the stator 1 is rigidly affixed to an upper supporting bar of the elevator main frame 8 and the other end thereof is connected to a supporting apparatus 50 of the lower supporting bar of the elevator main frame 8. Both sides of the square frame member 4 mounting the rotor 2 are slidably in contact with a pair of parallel guide rails 7 mating with the both sides thereof, which are spaced apart from each other and by a predetermined distance from the stator 1, respectively. Therefore, the rotor 2 moves slidably linearly up and down along the stator 1 with a guide of the guide rail 7.
There is formed an air gap between the outer surface of the stator 1 and the inner surface of the bore hole of the rotor 2 for maintaining a predetermined distance therebetween, and on the rotor 2 are disposed a plurality of air gap adjusting rollers 3 for maintaining a predetermined gap therebetween. Here, the air gap adjusting rollers 3 slide along the circumferencial surface of the stator 1.
Therefore, in operation of the linear motor the rotor 2 slides linearly up and down along the stator 1 and the square frame member 4 mounting the rotor 2 slides linearly along the guide rails 7, whereby the car 5 goes up and down according to the movement of the square frame member 4.
The supporting apparatus 50, which is for substantially reducing the vibration load from the stator 1 in operation of the elevator, as shown in FIG. 2 includes a turn buckle 12 connected to the lower end of the stator 1 and a coil spring 11 whose one end is connected to the turn buckle 12 and whose other end is connected to the elevator main frame 8. The supporting apparatus 50 is described in detail with a reference to FIG. 3.
The lower end of the stator 1 of the linear motor is connected to the upper portion of a yoke 14 by a pin 14'. The lower portion of the yoke 14 rotatably receives an upper ring of a ball joint 13. A circular ring 9 integrally formed with the ball joint 13 is connected with an upper hook ring 16 of the hollow cylindrical turn buckle 12. A lower hook ring 16' of the turn buckle 12 is connected with an upper end of the coil spring 11 having a predetermined elastic property. The lower end of the coil spring 11 is connected with a ring 10 connected to the elevator main frame 8.
The turn buckle 12 and the coil spring 11 are designed for controlling the tensile force upon the stator 1, which is caused according to the movement of the rotor 2 in operation of the elevator. The stator 1 receives the vibration and impact thereof because when the stator 1 and the elevator main frame 8 are rotatably freely connected with each other, as here, when the stator 1 is forcibly vibrated, then the vibration load is dampened by the coil spring 11 of the supporting apparatus 50.
However, when the rotor 2 linearly correctly moves along the stator 1 in a vertical direction, as explained above, the conventional supporting apparatus 50 effectively works to dampen the vibration load and impact therefrom. On the contrary, when the rotor 2 and the stator 1 does not move up and down in a vertical direction correctly, the supporting apparatus 50 cannot substantially dampen the vibrations and impacts therefrom and thus the safe operation of the elevator cannot be secured. Designing the stator 1 and the rotor 2 to be correctly coincident in a vertical direction is in fact originally difficult. In this case the relative displacement between the stator 1 and the rotor 2 are directed to the load of the air gap adjusting rollers 3 disposed both at lower and upper portions of the rotor 2, thereby causing one-sided abrasion thereof and thus the safety operation of the elevator cannot be secured.